Tobacco substitute smoking mixture

ABSTRACT

Tobacco substitute based smoking mixture with added protein and a carotenoid. The protein imparts tobacco-like flavour and after-taste to the smoke of the mixture and the carotenoid masks any protein offnotes and imparts a fresh vegetable-like effect to the smoke. The substitute mixture fuel is essentially a thermally degraded carbohydrate prepared by subjecting carbohydrate to a catalysed degradation at temperatures of up to 250*C.

[451 Oct. 29, 1974 TOBACCO SUBSTITUTE SMOKING MIXTURE [75] Inventor: Colin James Webster, West Kilbride, Scotland [73] Assignee: Imperial Chemical Industries,

Limited, London, England 22 Filed: Mar. 18,1971

21 App1.No.: 125,806

[30] Foreign Application Priority Data Mar. 23, 1970 Great Britain 13861/70 [52] US. Cl ..131/2,131/9,131/144 [51] Int. Cl A24b 15/00 [58] Field of Search 131/2, 15, 17, 140-144 [56] References Cited UNITED STATES PATENTS 2,171,986 9/1939 Poetschke 131/15 R 2,460,284 1/1949 Hale 131/15 R 2,576,021 11/1951 Koree 131/2 2,890,973 6/1959 Fachini 131/15 R 3,047,433 7/1962 Bavley et a1. 131/17 R 3,145,717 8/1964 Osborne et a1. 131/17 AE 3,312,226 4/1967 Bavley 131/17 R 3,364,935 1/1968 Moshy et al 131/140 P 3,461,879 8/1969 Kirkland 131/2 3,525,582 8/1970 Waterbury 131/9 3,542,677 11/1970 Theimer 131/17 R X 3,545,488 12/1970 Troon et a1. 131/2 FOREIGN PATENTS OR APPLICATIONS 687,507 3/1967 Belgium 131/2 908,439 10/1962 Great Britain 131/17 Primary ExaminerMelvin D. Rein Attorney, Agent, or Firm-Cushman, Darby & Cushman [57] ABSTRACT Tobacco substitute based smoking mixture with added protein and a carotenoid.

The protein imparts tobacco-like flavour and after-taste to the smoke of the mixture and the carotenoid masks any protein off-notes and imparts a fresh vegetable-like effect to the smoke. The substitute mixture fuel is essentially a thermally degraded carbohydrate prepared by subjecting carbohydrate to a catalysed degradation at temperatures of up to 250C.

8 Claims, N0 Drawings 1 TOBACCO SUBSTITUTE SMOKING MIXTURE This invention relates to a smoking mixture suitable for incorporation in cigars, cigarettes and smoking pipes, in total or partial replacement of the tobacco constituent of the mixtures normally used.

Smoking mixtures normally consist mainly of, or contain a high proportion of natural tobacco and the opinion is now widely held that the smoking of tobacco, especially in cigarette form, increases the incidence of lung cancer and bronchitic ailments. The replacement of tobacco in smoking mixtures by cellulose and other smoke-producing materials has been proposed but such proposed mixtures have not been acceptable to smokers because the smoke flavour was excessively different from that of tobacco smoke.

In a copending application there is disclosed a smoking mixture comprising an organic combustible material as smoke-producing fuel, e.g., carbohydrate, modified carbohydrate or certain aldol condensation products, in admixture with protein. The protein serves to reduce or eliminate the intensity of the off-odours and off-flavours of the smoke from the smoke-producing material and also imparts a tobacco-like flavour and after-taste to the smoke. Such an improved smoking mixture containing protein to mask the unpleasant character of the smoke is not, however, entirely satisfactory since the protein itself can give rise to off-notes or odours.

An object of the present invention is to improve on the protein containing smoking mixtures of referred to by including an ingredient which masks the protein offnotes of the smoke from said mixtures.

According to the present invention there is provided a smoking mixture comprising an organic combustible material as smoke-producing fuel, protein and a conjugated polyunsaturated isoprenoid or derivatives thereof such as acids and esters.

We have discovered that the conjugated polyunsaturated isoprenoids are successful in imparting a fresh vegetable-like effect to the aforementioned proteincontaining smoking mixtures.

We have further discovered that if the conjugated polyunsaturated isoprenoid contains ionone rings at the end of the hydrocarbon chains then the vegetable effeet is enhanced.

The smoking mixture may comprise 0.5 to 25 percent by weight of protein and up to 4 percent by weight of the polyunsaturated isoprenoid or derivative thereof, the remainder being made up of the smoke-producing fuel, additives and fillers. The preferred amount of protein is l to 6 percent by weight and the preferred amount of isoprenoid is 0.001 to 0.5 percent by weight.

The smoking mixtures of the invention will, in addition to protein, conjugated polyunsaturated isoprenoid and the smoke-producing fuel, contain other ingredients such as are normally used in smoking mixtures to impart desired physical properties and burning characteristics. For example, the mixtures may comprise glow-controlling catalysts, materials to improve ash coherence and colour, nicotine, flavourants, medicaments and humectants or film-forming binding agents. The mixtures may also contain tobacco as part of the smoke-producing material. Such added tobacco could be in the form of comminuted tobacco or tobacco shred.

Alkali metal compounds may advantageously be used as glow-controlling catalysts and salts of ammonia, alkali metals or alkaline earth metals may be used as ash improvers.

Alkali or alkaline earth carbonates or porous fillers may be incorporated in the smoking mixtures to give an open texture and facilitate combustion.

More particularly, additional compounds may comprise:

l. Fillers e.g., calcium carbonate, magnesium carbonate.

2. Humectants e.g., glycerol, ethylene glycol, polyethylene glycol.

3. Film-forming agents e.g., methyl cellulose, so-

dium carboxymethyl cellulose, pectins, gums.

4. Glow-controlling catalysts e.g., potassium citrate, calcium carbonate, magnesium carbonate.

5. Ash cohesion agents e.g., citric acid, sodium hydrogen phosphate, tobacco extracts.

6. Solanesol, other similar unconjugated polyisoprenoids and derivatives thereof (e. g., esters, acids and hydroxyl derivatives), may be added to obtain a sweetish aroma from the burning mixture and to give a pleasant after-note in the mouth of the smoker.

The smoking mixture containing modified carbohydrate and aldol condensation product may additionally contain as a minor component one or more carbohydrate materials such as cellulose fibre, starch or sugar, to improve flavour and physical properties.

The conjugated polyunsaturated isoprenoid is preferably a carotenoid. It may also be a Vitamin A derivative.

The carotenoid is preferably carotene or a carotene derivative. Suitable carotenoids include a-carotene, B-carotene, admixtures of aand ,B-carotene with 'y-carotene, lycopene, l5} l5 dehydro- Bcarotene, 4,- 4 -diketol 5, l 5 -dehydro-fi-carotene, bixin, apocarotenal, apocarotenoic acid derivatives, canthanxanthin or other xanthophylls.

A naturally occurring isomeric mixture consisting of percent B-carotene and 15 percent a-carotene may advantageously be used but pure (1- or pure B-carotene is also suitable.

The smoke-producing fuel may be a carbohydrate material.

The carbohydrate material may advantageously comprise a-cellulose, cellulose derivatives, sugars, starch, alginate, pectin or natural gum.

The smoke-producing fuel may be a modified carbohydrate.

The modified carbohydrate may advantageously be prepared as disclosed in US. Pat. No. 3,545,448 by subjecting it to a catalysed degradation process at a temperature of l00-250C until the weight of the degraded material is less than percent of the dry weight of the original carbohydrate.

Preferred degradation catalysts include sulphuric acid, sulphamic acid and ammonium sulphamate, and the preferred modified carbohydrate is thermally degraded cellulose.

The protein should preferably be pure and it is desirable, but not essential, that any residual fat should be removed from the protein, for example, by extraction with an organic solvent. Especially valuable proteins include animal protein, for example, albumin, casein, gelatine, peptone, haemoglobin or wool protein and vegetable proteins, for example, protein from maize (zein), wheat (glutin and gliadin), soyabean or groundnut.

Protein acid hydrolysates and protein enzyme hydrolysates, e.g., casein acid hydrolysate and casein enzyme hydrolysates, are also suitable for the purpose of the invention.

The ratio of protein to smoke-producing fuel in the smoking mixture is in the range 1:1 to 1:60 preferably 1:8 to 1:30.

The smoking mixture is preferably prepared in a form simulating tobacco. Thus it is preferred to form the mixed ingredients into a sheet and cut or shred the sheet into the physical form required. 1f the carbohydrate or modified carbohydrate used is already sheeted, the smoking mixture may be prepared by merely treating the sheet with the remaining ingredients. In the usual case, where the carbohydrate is in divided form, the ingredients may be admixed and subsequently sheeted. To facilitate sheeting it is advantageous to incorporate a solution of a binding agent, for example, water-solublecellulose ether, polyvinyl alcohol or a water-soluble gum, in the mixture.

The carotene or other conjugated polyunsaturated isoprenoid is advantageously sprayed from solution on to the shredded substrate. Without protein, the addition of the polyunsaturated isoprenoid has little influence on the flavour of the smoke-producing substrate. The effect is thus synergistic between the isoprenoid hydrocarbon and protein.

The invention is further illustrated by the following Examples in which all parts and percentages are by weight. In each of the Examples the flavour and aftertaste of the product was assessed by a panel of smokers. Furthermore, in each of the Examples those ingredients which are not soluble are to be considered as being finely divided.

EXAMPLE 1 2.8 parts of glycerol, 0.8 part citric acid and 1 part of potassium citrate dissolved in parts distilled water were mixed with 2 parts sodium carboxymethyl cellulose dissolved in 80 parts hot distilled water. 0.88 part of the protein casein (extracted for 48 hours with petroleum ether at 30C), 2 parts calcium carbonate and 10.52 parts of a material made by heating oz-cellulose impregnated with 0.51 part of ammonium sulphamate for up to 4 hours at 200C were added to the above mixture and the whole stirred until homogeneous (about 1 hour).

The slurry is cast on glass plates and dried to give a film 0.006 in. thick which is removed from the plates, cut and shredded. The shred is sprayed with a solution of 0.04 part ,B-carotene in 35 parts carbon tetrachloride and the solvent allowed to evaporate. When the treated shred is made into cigarettes and smoked, it shows features of a vegetable taste and after-taste which is tobacco-like.

EXAMPLE 2 2.8 parts of glycerol, 0.8 part citric acid and 1 part of potassium citrate dissolved in 20 part distilled water were mixed with 2 parts sodium carboxymethyl cellulose dissolved in 80 parts hot distilled water. 0.88 part of the protein 'zein (extracted for 48 hours with petroleum ether at 30C), 2 parts calcium carbonate and 10.52 parts of a material made by heating a-cellulose impregnated with 0.51 part of ammonium sulphamate for up to 4 hours at 200C were added to the above mixture and the whole stirred until homogeneous (about 1 hour).

The slurry is cast on glass plates and dried to give a film 0.006 in. thick which is removed from the plates, cut and shredded. The shred is sprayed with a solution of 0.04 part ,B-carotene in 35 parts carbon tetrachloride and the solvent allowed to evaporate. When the treated shred is made into cigarettes and smoked, it shows features of a vegetable taste and after-taste which is tobacco-like.

EXAMPLE 3 1.34 parts of glycerol and 0.78 part of potassium citrate dissolved in 4 parts distilled water were mixed with 1.92 parts of sodium carboxymethyl cellulose dissolved in 96 parts hot distilled water. 6.73 parts of magnesium carbonate (magnesite), 3.86 parts of calcium carbonate, 0.42 parts of the protein casein (extracted for 48 hours with petroleum ether at 30C) and 4.95 parts of a material made by heating a-cellulose with ammonium sulphamate for up to 4 hours at 200C, were added to the above mixture and the whole stirred until homogeneous (about 1 hour).

The slurry is cast on glass plates and dried to give a film 0.006 in. thick which is removed from the glass plates, cut and shredded. The shred is sprayed with a solution of 0.02 part of B-carotene in 35 parts carbon tetrachloride and the solvent allowed to evaporate. When the treated shred is made into cigarettes and smoked, it shows features of a vegetable taste and aftertaste which is tobacco-like.

EXAMPLE 4 2.8 parts of glycerol, 0.8 part citric acid and 1 part of potassium citrate dissolved in 20 parts distilled water were mixed with 2 parts sodium carboxymethyl cellulose dissolved in parts hot distilled water. 0.88 part of of the protein casein (extracted for 48 hours with petroleum ether at 30C 2 parts calcium carbonate and 10.52 parts of a material made by heating a-cellulose impregnated with 0.51 part of ammonium sulphamate for up to 4 hours at 200C were added to the above mixture and the whole stirred until homogeneous (about 1 hour).

The slurry is cast on glass plates and dried to give a film 0.006 in. thick which is removed from the plates, cut and shredded. The shred is sprayed with a solution of 0.04 part vitamin A acetate in 35 parts carbon tetrachloride and the solvent allowed to evaporate. When the treated shred is made into cigarettes and smoked, it shows features of a vegetable taste and after-taste which is tobacco-like.

EXAMPLE 5 2.8 parts of glycerol, 0.8 part citric acid and 1 part of potassium citrate dissolved in 20 parts distilled water were mixed with 2 parts sodium carboxymethyl cellulose dissolved in 80 parts hot distilled water. 0.88 part of the protein casein (extracted for 48 hours with petroleum ether at 30C), 2 parts calcium carbonate and 10.52 parts of a material made by heating a-cellulose impregnated with 0.51 part of ammonium sulphate for up to 4 hours at 200C, were added to the above mixture and the whole stirred until homogeneous (about 1 hour).

The slurry is cast on glass plates and dried to give a film 0.006 in. thick which is removed from the plates, cut and shredded. The shred is sprayed with a solution of 0.04 part canthaxanthin in 35 parts carbon tetrachloride and the solvent allowed to evaporate. When the treated shred is made into cigarettes and smoked, it shows features of a vegetable taste and after-taste which is tobacco-like.

EXAMPLE 6 2.8 parts of glycerol, 0.8 part citric acid and 1 part potassium citrate dissolved in parts distilled water were mixed with 2 parts sodium carboxymethyl cellulose dissolved in 80 parts hot distilled water. 0.88 part of the protein casein (extracted for 48 hours with petroleum ether at C), 2 parts calcium carbonate and 10.52 pans of a material made by heating u-cellulose impregnated with 0.51 part of ammonium sulphamate for up to 4 hours at 200C were added to the above mixture and the whole stirred until homogeneous (about 1 hour).

The slurry is cast on glass plates and dried to give a film 0.006 in. thick which is removed from the plates, cut and shredded. The shred is sprayed with a solution of 0.04 part lycopene in parts carbon tetrachloride and the solvent allowed to evaporate. When the treated shred is made into cigarettes and smoked, it shows features of a vegetable taste and after-taste which is tobacco-like.

EXAMPLE 7 1.34 parts of glycerol and 0.78 part of potassium citrate dissolved in 4 parts distilled water were mixed with 1.92 part of sodium carboxymethyl cellulose dissolved in 96 parts hot distilled water. 6.73 parts of magnesium carbonate (magnesite), 3.86 parts of calcium carbonate, 0.38 part of the protein casein (extracted for 48 hours with petroleum ether at 30C and 5.0 parts of a material made by heating a-cellulose with ammonium sulphamate for up to 4 hours at 200C were added to the above mixture and stirred until homogeneous (about 1 hour).

The slurry was cast on glass plates and dried to give a film 0.006 in. thick which was removed, from the plates, cut and shredded. The shred was sprayed with a solution of 0.02 part of a naturally occurring isomeric mixture of 15 percent aand 85 percent B-carotene in 50 parts carbon tetrachloride and the solvent allowed to evaporate. When the treated shred was made into cigarettes, it showed features of a vegetable taste and after-taste which is tobacco-like.

EXAMPLE 8 1.34 parts of glycerol and 0.78 part of potassium citrate dissolved in 4 parts distilled water were mixed with 1.92 parts of sodium carboxymethyl cellulose dissolved in 96 parts hot distilled water. 6.72 parts of magnesium carbonate (magnesite), 3.86 parts of calcium carbonate, 0.2 part of the protein casein (extracted for 48 hours with petroleum ether at 30C), and 5.18 parts of a material made by heating a-cellulose with ammonium sulphamate for up to 4 hours at 200C, were added to the above mixture and the whole stirred until homogeneous (about 1 hour).

The slurry was cast on to glass plates and dried to give a film 0.006 in. thick which was removed from the plates, cut and shredded. This shred was sprayed with a solution of 0.01 part B-carotene in 35 parts carbon tetrachloride and the solvent allowed to evaporate. When the treated shred was made into cigarettes in a 50:50 blend with flue-cured tobacco shred and smoked in comparison with a similar blend not containing B-carotene, there was a marked preference for the cigarette containing the additive because of the presence of a fuller flue-cured flavour.

A similar result was obtained in similar exercises using either :30 or :15 shred/shred blends of artificial substrate and tobacco.

EXAMPLE 9 1.8 parts of glycerol dissolved in 4 parts of distilled water were mixed with 2.4 parts sodium carboxymethyl cellulose dissolved in 96 parts distilled water. 5.98 parts of magnesium carbonate (magnesite), 3.44 parts of calcium carbonate, 0.3 parts of soya fibre protein, 1 part of bentonite and 5.08 parts of a material made by heat ing alpha-cellulose with ammonium sulphamate were added to the above mixture and the whole stirred until homogeneous (about 1 hour).

The slurry was cast on glass plates and dried to give a film 0.006 in. thick. The film was removed and shredded. The shred was sprayed with a solution of 0.02 part carotene in 50 parts chloroform and the solvent allowed to evaporate. When the treated shred was made into cigarettes and smoked, it shows features of a vegetable taste and after-taste which are tobacco like.

EXAMPLE 10 1.32 parts of glycerol dissolved in 4 parts of distilled water were mixed with 1.8 parts sodium carboxymethyl cellulose dissolved in 96 parts distilled water. 4.48 parts of magnesium carbonate (magnesite), 2.58 parts of calcium carbonate, 5.0 parts of protein casein, 0.74 parts of bentonite and 3.96 parts of a material made by heating a-cellulose with ammonium sulphamate were added to the above mixture and the whole stirred until homogeneous (about 1 hour).

The slurry was cast on glass plates and dried to give a film 0.006 in. thick. The film was removed and shredded. The shred was sprayed with a solution of 0.02 part of carotene in 50 parts chloroform and the solvent allowed to evaporate. When the treated shred was made into cigarettes and smoked, it shows features of a vegetable taste and after taste.

EXAMPLE 1 l 1.8 parts of glycerol dissolved in 4 parts distilled water were mixed with 2.4 parts sodium carboxymethyl cellulose dissolved in 96 parts distilled water. 5.98 parts of magnesium carbonate (magnesite), 3.44 parts of calcium carbonate, 0.3 parts of the protein gliadin, 1 part of bentonite and 5.08 part of a material made by heating a-cellulose with ammonium sulphamate were added to the above mixture and the whole stirred until homogeneous (about 1 hour).

The slurry was cast on glass plates and dried to give a film 0.006 in. thick. The film was removed and shredded. The shred was sprayed with a solution of 0.02 part of carotene in 50 parts chloroform and the solvent allowed to evaporate. When the treated shred was made into cigarettes and smoked, it shows features of a vegetable taste and after taste.

EXAMPLE 12 1.8 parts of glycerol dissolved in 4 parts of distilled water were mixed with 2.4 parts sodium carboxymethyl cellulose dissolved in 96 parts distilled water. 5.98 parts of magnesium carbonate (magnesite), 3.44 parts of calcium carbonate, 2.69 parts of protein casein, l part of bentonite and 2.68 parts a material made by heating a-cellulose with ammonium sulphamate were added to the above mixture and the whole stirred until homogeneous (about 1 hour).

The slurry was cast on glass plates and dried to give a film 0.006 in. thick. The film was removed and shredded. The shred was sprayed with a solution of 0.02 part of carotenein 50 parts ether and the solvent allowed to evaporate. When the treated shred was made into cigarettes and smoked, it shows features of a vegetable taste and after-taste which are tobacco-like.

EXAMPLE 13 1.8 parts of glycerol dissolved in 4 parts of distilled water were mixed with 2.4 parts sodium carboxymethyl cellulose dissolved in 96 parts distilled water. 5.98 parts of magnesium carbonate (magnesite), 3.44 parts of calcium carbonate 0.088 parts of protein casein and 1 part of bentonite and 5.30 parts of a material made by heating a-cellulose with ammonium sulphamate were added to the above mixture and the whole stirred until homogeneous (about 1 hour).

The slurry was cast on glass plates and dried to give a film 0.006 in. thick. The film was removed and shredded. The shred was sprayed with a solution of 0.02 part of carotene in 50 parts ether and the solvent allowed to evaporate. When the treated shred was made into cigarettes and smoked it shows features of a vegetable taste and after-taste which are tobacco-like.

EXAMPLE 14 1.8 parts of glycerol dissolved in 4 parts of distilled water were mixed with 2.4 parts sodium carboxymethyl cellulose dissolved in 96 parts distilled water. 5.98 parts of magnesium carbonate (magnesite), 3.44 parts of calcium carbonate, 0.3 parts of protein casein, 1 part of bentonite and 5.08 parts of a material made by heating a-cellulose with ammonium sulphamate were added to the above mixture and the whole stirred until homogeneous (about l hour).

The slurry was cast on glass plates and dried to give a film 0.006 in. thick. The film was removed and shredded. The shred was sprayed with a solution of 0.04 parts of apocarotenal in 50 parts chloroform and the solvent allowed to evaporate. When the treated shred was made into cigarettes and smoked in comparison with a similar cigarette not containing the sprayed on additive, there was a marked preference for the cigarette with the additive because of improved tobacco character.

EXAMPLE 15 1.8 parts of glycerol dissolved in 4 parts of distilled water were mixed with 2.4 parts sodium carboxymethyl cellulose dissolved in 96 parts distilled water, 5.98 parts of magnesium carbonate (magnesite), 3.44 parts of calcium carbonate, 0.3 parts of protein casein, 1 part of bentonite and 5.08 parts of a material made by heating a-cellulose with ammonium sulphamate were added to the above mixture and the whole stirred until homogeneous (about 1 hour).

The slurry was cast on glass plates and dried to give a film 0.006 in. thick. The film was removed and shredded. The shred was sprayed with a solution of 0.4 part Vitamin A acetate in 50 parts chloroform and the solvent allowed to evaporate. When the treated shred was made into cigarettes and smoked in comparison with a similar cigarette not containing the sprayed on additive, there was a marked preference for the cigarettes with the additive because of improved tobacco character.

What is claimed is:

1. A smoking mixture for cigars, cigarettes and pipes as a tobacco replacement, said mixture comprising as the smoke-producing fuel thermally degraded carbohydrate prepared by subjecting carbohydrate to a catalyzed degradation process at a temperature of at least 100C. until the weight of the degraded material is less than percent of the dry weight of the original carbohydrate, 0.5 to 25 percent by weight protein which is essentially pure and free of residual fat, said protein being capable of supporting combustion and being selected from the group consisting of albumin, casein, gelatin peptone, haemoglobin, wool, maize, wheat, soyabean and groundnut proteins, and functioning to reduce off-odors or off-flavors of the smoke from said fuel and up to 4 percent by weight of carotenoid to mask any protein off-notes of the smoke from said mixture.

2. A smoking mixture as claimed in claim 1 comprising 1 to 6 percent by weight protein and 0.001 to 0.5 percent by weight carotenoid.

3. A smoking mixture as claimed in claim 1 wherein the ratio of protein to smoke-producing fuel is 1:1 to 1:60.

4. A smoking mixture as claimed in claim 3 wherein the ratio of protein to smoke-producing fuel is 1:8 to 1:30.

5. A smoking mixture as claimed in claim 1 wherein the carbohydrate is a-cellulose, cellulose derivatives, sugars, starch, alginate, pectin or natural gum.

6. A smoking mixture as claimed in claim 1 wherein the carotenoid is carotene.

7. A smoking mixture as claimed in claim 1 wherein the carotenoid is a-carotene, B-carotene, admixtures of ozand ,B-carotene with 'y-carotene, lycopene, 15, l S -dehydrO-B-carotene, 4,4 -diketo-l 5 ,l 5 dehydro- B-carotene, bixin, apocarotenal, apocarotenoic acid derivatives, canthanxanthin or other xanthophylls.

8. A smoking mixture as claimed in claim 1 wherein the carotenoid is a naturally occurring isomeric mixture of aand ,B-carotene. 

1. A SMOKING MIXTURE FOR CIGARS, CIGARETTES AND PIPES AS A TOBACCO REPLACEMENT, SAID MIXTURE COMPRISING AS THE SMOKEPRODUCING FUEL THERMALLY DEGRADED CARBONHYDRATE PREPARED BY SUBJECTING CARBONHYDRATE TO A CATALYZED DEGRADATION PROCESS AT A TEMPERATURE OF AT LEAST 100*C. UNTIL THE WEIGHT OF THE DEGRADED MATERIAL IS LESS THAN 90 PERCENT OF THE DRY WEIGHT OF THE ORIGINAL CARBOHYDRATE, 0.5 TO 25 PERCENT BY WEIGHT PROTEIN WHICH IS ESSENTIALLY PURE AND FREE OF RESIDUAL FAT, SAID PROTEIN BEING CAPABLE OF SUPPORTING COMBUSTION AND BEING SELECTED FROM THE GROUP CONSISTING OF ALBUMIN, CASEIN, GELATIN PEPTON, HAEMOGLOBIN, WOOL, MAIZE, WHEAT, SOYBEAN AND GROUNDNUT PROTEINS, AND FUNCTIONING TO REDUCE OFF-ODORS OR OFF-FLAVORS OF THE SMOKE FROM SAID FUEL AND UP TO 4 PERCENT BY WEIGHT OF CAROTENOID TO MASK ANY PROTEIN OFF-NOTES OF THE SMOKE FROM SAID MIXTURE.
 2. A smoking mixture as claimed in claim 1 comprising 1 to 6 percent by weight protein and 0.001 to 0.5 percent by weight carotenoid.
 3. A smoking mixture as claimed in claim 1 wherein the ratio of protein to smoke-producing fuel is 1:1 to 1:60.
 4. A smoking mixture as claimed in claim 3 wherein the ratio of protein to smoke-producing fuel is 1:8 to 1:30.
 5. A smoking mixture as claimed in claim 1 wherein the carbohydrate is Alpha -cellulose, cellulose derivatives, sugars, starch, alginate, pectin or natural gum.
 6. A smoking mixture as claimed in claim 1 wherein the carotenoid is carotene.
 7. A smoking mixture as claimed in claim 1 wherein the carotenoid is Alpha -carotene, Beta -carotene, admixtures of Alpha - and Beta -carotene with gamma -carotene, lycopene, 151, 151-dehydro- Beta -carotene, 4,41-diketo-15,151 dehydro- Beta -carotene, bixin, apocarotenal, apocarotenoic acid derivatives, canthanxanthin or other xanthophylls.
 8. A smoking mixture as claimed in claim 1 wherein the carotenoid is a naturally occurring isomeric mixture of Alpha -and Beta -carotene. 